Metrolinx used to be known as the Greater Toronto Transportation Authority (GTTA). Legislation to create the GTTA was introduced in the Legislative Assembly of Ontario on April 24, 2006, and was passed and received royal assent on June 22, 2006. In April 2007, a transition team seconded from the Ontario Public Service began work at the GTTA's headquarters at 20 Bay Street in Toronto.

In July 2007, the GTTA identified the following first round of ‘Quick Win’ projects as candidates for early implementation:

GO Transit rail fleet expansion

$60.0 million for 20 new bi-level passenger coaches

$20.0 million for track capacity expansion

GO Transit Bus fleet expansion

$9.0 million for 10 new double-decker coaches

Markham/Cornell Transit Terminal

Hamilton/Upper James Rapid Transit Corridor

Integrated Web-Based Trip Planner Pilot

Carbon Footprint Calculator

Bicycle promotion initiatives

$2.1 million-$3.2 million for safe/secure bike storage

$1.0 million-$1.8 million to expand bike/bus rack program

On December 4, 2007, the GTTA adopted the name ‘Metrolinx’ for public use. At the same time, it launched a new web site, and released the first of its series of green papers on transportation issues, part of the process of creating the Regional Transportation Plan.

In June 2008, Metrolinx began using a new logo in printed and electronic communications.

On December 17, 2008, Metrolinx announced that, together with twelve municipalities, it had made a collective bus purchase for 160 buses.[1]

On March 30, 2009, the Ontario government introduced legislation to merge GO Transit and Metrolinx as a single entity, with "Metrolinx" as its legal name.[2] The legislation received royal assent on May 14, 2009, taking immediate effect. This resulted in the replacement of the previous board structure with a new one in which 15 private-sector appointees are made by the province. The legislation makes other changes to Metrolinx's powers and abilities.

Originally GO's trackage was owned entirely by Canada's two major commercial railways: the large majority by the Canadian National Railway (CNR) and the remainder by Canadian Pacific Railway (CPR). Before Metrolinx's creation, GO Transit had only acquired partial ownership of the Lakeshore East, Barrie, Stouffville and Milton lines. However, ever since its inception Metrolinx has been aggressively expanding its ownership of the rail corridors GO transit operates on by acquiring nonessential rail lines from both CN and CP.

On December 15, 2009, Metrolinx announced that it had acquired the lower portion of the Newmarket subdivision for $68 million from CN, giving it full ownership of the Barrie line.[6]

On March 31, 2010, Metrolinx announced that it had acquired a key piece of track from CN for $168 million.[7] This purchase was for a portion of the Oakville subdivsion from Union station to 30th Street in Etobicoke just west of GO's Willowbrook yard.

On March 30, 2011, Metrolinx announced that it had acquired the portion of the Kingston line on which that GO trains operate from CN for $299 million, giving them full ownership of the Lakeshore East line.[10]

On June 16, 2011, Metrolinx announced that, together with 12 municipalities, it purchased 287 new transit buses.[11]

On August 24, 2011, Metrolinx division GO Transit announced that the Presto Card is available across its entire GTHA network.[12]

On March 27, 2012, Metrolinx announced that it had acquired key portions of multiple subdivisions from CN for $310.5 million. This purchase included the southern portions of the Bala subdivision up to CN's main east-west freight line the York subdivision, part of the Richmond Hill line and a large portion of the Oakville subdivision from 30th Street in Etobicoke to a point just west of Fourth line in Oakville.[15]

On May 10, 2012, GO Transit announced summer weekend and GO train service between Toronto and Barrie.[16]

On November 15, 2012, GO Transit launched the GO Train Service Guarantee, a fare credit policy for train delays.[17]

On November 29, 2012, Metrolinx announced the Next Wave of Big Move projects.[18]

On March 22, 2013, Metrolinx completed an additional purchase of the Oakville subdivision from CN for $52.5 million. This purchase was for the portion from Fourth Line in Oakville to a point just east of where CN's freight main line joins the Oakville Subdivision in Burlington.[20]

On April 13, 2013, it was announced that Metrolinx division Presto would make its smart farecard available across the entire OC Transpo network in Ottawa.[21]

On May 27, 2013, Metrolinx announced its Investment Strategy, a series of recommendations for sustaining transit growth in the region.[22]

As of June 2013, Metrolinx had ownership of 68% of the corridors on which it operates, up from 6% in 1998.[23] It has complete ownership of the Barrie, Stouffville and Lakeshore East lines and majority ownership of the Lakeshore West line (to a point just West of Burlington GO station) and Richmond Hill line (to Doncaster Junction, a point in between Old Cummer and Langstaff GO stations). Metrolinx owns comparatively small portions of the Kitchener and Milton lines, a situation that is unlikely to change as the lines are heavily used by freight traffic.

On June 5, 2013, Metrolinx crews began tunnelling the western underground portion of the Eglinton Crosstown.[24]

On June 28, 2013, GO Transit introduced its biggest expansion in 46 years with 30-minute service on the Lakeshore lines.[25]

The Metrolinx Act of 2006, formerly known as the Greater Toronto Transportation Authority Act of 2006, describes two of Metrolinx's primary responsibilities as being:[33]

to provide leadership in the co-ordination, planning, financing and development of an integrated, multi-modal transportation network that conforms with transportation polices of growth plans prepared and approved under the Places to Grow Act, 2005 applicable in the regional transportation area and complies with other provincial transportation policies and plans applicable in the regional transportation area, and

to act as the central procurement agency for the procurement of local transit system vehicles, equipment, technologies and facilities and related supplies and services on behalf of Ontario municipalities.

The Big Move: Transforming Transportation in the Greater Toronto and Hamilton Area was one of Metrolinx's first deliverables. It is a Regional Transportation Plan (RTP) including a rolling five-year capital plan and Investment Strategy for the GTHA. The plan builds on 52 GO train, subway, light rail and bus rapid transit projects proposed by the Government of Ontario in its MoveOntario 2020 plan announced on June 15, 2007, and includes new projects to support them.

A draft version of the Regional Transportation Plan was provided to Metrolinx on September 26, 2008, and a final version was approved on November 27, 2008.[34]

The Investment Strategy proposes a series of 24 recommendations as part of a four-part plan to integrate transportation, growth and land use planning in the GTHA, maximize the value of public infrastructure investment, optimize system and network efficiencies, and dedicate new revenue sources for transit and transportation.

Within the Investment Strategy, Metrolinx made twenty-four recommendations, including investment tools and policy recommendations.

Canada's first such public system, GO Transit began regular passenger service on May 23, 1967, under the auspices of the Ontario Ministry of Transportation. Over time it has been constituted in a variety of public-sector configurations, but it became an operating division of Metrolinx in 2009.

New and improved GO service is a top transit priority listed in The Big Move. Since 2009, GO Transit has introduced seasonal train service to Barrie and Niagara Falls, extended service to Kitchener and Lake Simcoe, opened four new stations at Acton, Guelph Central, Kitchener and Allandale Waterfront. As of June 2013, GO Trains along the Lakeshore rail lines run every 30 minutes, making the biggest expansion in GO Transit history. [37]

The line will operate along a Metrolinx-owned railway rail corridor now used by GO Transit, that is under construction as part of the Georgetown South Project to allow for additional train traffic. The UP Express will share the same path as trains on the Kitchener line, before splitting off onto a separate spur just north of the Etobicoke North Station. It will also stop at the existing Bloor and Weston GO Stations.

Construction of the Union Pearson Express is 100% underway, and service will begin the spring of 2015.

The Presto card, originally known as the GTA Farecard, is a smartcard-based fare payment system for public transit systems in Ontario, including those in the Greater Toronto and Hamilton Area and Ottawa. The Presto system is designed to support the use of one common farecard for fare payment on various public transit systems, through electronic readers that calculate the correct fare and deduct it from a preloaded balance.

Presto will also centralize its operational logistics, such as farecard procurement, reporting services, and a customer call centre. The system was trialled from June 25, 2007 to September 30, 2008. Full implementation began in November 2009. It will be rolled out across the province in stages. Presto now serves over a million customers in the GTHA and Ottawa.

As of February 2014, Presto has been fully implemented on the following transit systems:

Smart Commute is a program that, with the support of local municipalities, tries to fight climate change by reducing traffic congestion and increasing transit efficiency. Employers and employees in the GTHA can explore and have assistance with different commuting options, such as carpooling, transit, cycling, walking, telework and flexible work hours. The program is delivered through local transportation management associations.[40]

Originally conducted under the Ontario Ministry of Transportation in 2006, the Transit Procurement Initiative involves Metrolinx assisting municipal transit operators with the procurement of vehicles, equipment, technologies, facilities and related supplies. The goal of the program is to reduce per unit cost, increase unit quality, and provide an open and transparent procurement process for municipal transit operators. To date, the program has supported 21 municipalities and transit agencies, has purchased over 400 buses, and has saved an estimated $5 million.[41]

Metrolinx also seeks partnerships with individuals and the community, and offers financial support for proposed projects that support transit.[42]

The agency has been[who?] criticized for not having enough executive power in planning transit outside of municipal politics, despite being established to take political delay out of transportation planning.[43] After Rob Ford was elected Mayor of Toronto in December 2010, he declared Transit City, the provincially funded transit expansion plan of light rail lines, dead. These lines were a large component of Metrolinx’s 2008 Big Move.[44] Metrolinx was again criticized when, in January 2012, its CEO declared that it would bend to what Toronto City Council wanted regarding how the Eglinton-Scarborough Crosstown LRT line should be built. The issue centred on whether the more suburban stretches of the line, from Laird Dr. to Kennedy Station, should be built at street level to save costs of building it underground.[45]

Metrolinx used to be governed by a board consisting of various appointees from the Ontario government and the regions within the GTHA. After the passage of the Greater Toronto and Hamilton Area Transit Implementation Act, 2009 merging Metrolinx and GO Transit, the Metrolinx board structure was changed, with politicians specifically prohibited from serving.